Recently, attention has been focused on a power feeding system (a noncontact power feeding system or a wireless charging system) that performs power supply (electricity transmission or power transmission) in a noncontact manner to CE devices (Consumer Electronics Devices) such as a mobile phone and a portable music player. Such a noncontact power feeding system makes it possible to start charge only by placing an electronic unit (a secondary unit) on a charging tray (a primary unit) instead of inserting (connecting) a connector, such as an AC adaptor, of a power supply unit into a unit. In other words, terminal connection between the electronic unit and the charging tray is not necessary.
An electromagnetic induction method is well known as a method of performing power supply in such a noncontact manner. Recently, attention is further focused on a noncontact power feeding system adopting a method referred to as magnetic resonance method using an electromagnetic resonant phenomenon. For example, PTL 1 to PTL 6 each disclose such a noncontact power feeding system.